clear all; clc; close all;

T=12*3600;
dT=T/1000;
t=0:dT:T;
Rz=6400*1000;
H=19100*1000;
R=Rz+H;
fi=(t/T)*2*pi;
Vsput=(2*pi*R)/T;

x=R*cos(fi);
y=R*sin(fi);

for i=1:(length(fi)-1)
Vx(i)=(x(i+1)-x(i))/dT;
Vy(i)=(y(i+1)-y(i))/dT;
V(i)=sqrt(Vx(i)^2+Vy(i)^2);
end;

plot(x,y);

Rsv=[x;y];
Rv=Rsv-Rz;

Vv(i)=-(V(i)*Rv/mod(Rv,0));



